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Ríos HA, Lövestam-Adrian M, Plainis S, Tsilimbaris M, Joussen AM, Keegan D, Charles M, Cunha-Vaz J, Midena E. Additional measures of macular function beyond visual acuity. Graefes Arch Clin Exp Ophthalmol 2024; 262:1723-1736. [PMID: 37938378 PMCID: PMC11106142 DOI: 10.1007/s00417-023-06272-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 09/29/2023] [Accepted: 10/09/2023] [Indexed: 11/09/2023] Open
Abstract
PURPOSE Visual function is a complex process in which external visual stimuli are interpreted. Patients with retinal diseases and prolonged follow-up times may experience changes in their visual function that are not detected by the standard visual acuity measure, as they are a result of other alterations in visual function. With the advancement of different methods to evaluate visual function, additional measurements have become available, and further standardization suggests that some methods may be promising for use in clinical trials or routine clinical practice. The objectives of this article are to review these additional measurements and to provide guidance on their application. METHODS The Vision Academy's membership of international retinal disease experts reviewed the literature and developed consensus recommendations for the application of additional measures of visual function in routine clinical practice or clinical trials. RESULTS Measures such as low-luminance visual acuity, contrast sensitivity, retinal fixation and microperimetry, and reading performance are measures which can complement visual acuity measurements to provide an assessment of overall visual function, including impact on patients' quality of life. Measures such as dark adaptation, color vision testing, binocular vision testing, visual recognition testing, and shape discrimination require further optimization and validation before they can be implemented in everyday clinical practice. CONCLUSION Additional measurements of visual function may help identify patients who could benefit from earlier diagnosis, detection of disease progression, and therapeutic intervention. New and additional functional clinical trial endpoints are required to fully understand the early stages of macular disease, its progression, and the response to treatment.
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Affiliation(s)
- Hernán Andrés Ríos
- Retina y Vítreo, Fundación Oftalmológica Nacional, Universidad del Rosario, Bogotá, Colombia
| | | | - Sotiris Plainis
- Laboratory of Optics and Vision, University of Crete Medical School, Heraklion, Crete, Greece
| | - Miltiadis Tsilimbaris
- Laboratory of Optics and Vision, University of Crete Medical School, Heraklion, Crete, Greece
| | | | - David Keegan
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | | | - José Cunha-Vaz
- AIBILI - Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | - Edoardo Midena
- Department of Ophthalmology, University of Padova, Padua, Italy.
- IRCCS Fondazione Bietti, Rome, Italy.
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Grissim G, Walesa A, Follett HM, Higgins BP, Goetschel K, Heitkotter H, Carroll J. Longitudinal Assessment of OCT-Based Measures of Foveal Cone Structure in Achromatopsia. Invest Ophthalmol Vis Sci 2024; 65:16. [PMID: 38587442 PMCID: PMC11005076 DOI: 10.1167/iovs.65.4.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 03/24/2024] [Indexed: 04/09/2024] Open
Abstract
Purpose Achromatopsia (ACHM) is an autosomal recessive retinal disease associated with reduced or absent cone function. There is debate regarding the extent to which cone structure shows progressive degeneration in patients with ACHM. Here, we used optical coherence tomography (OCT) images to evaluate outer nuclear layer (ONL) thickness and ellipsoid zone (EZ) integrity over time in individuals with ACHM. Methods Sixty-three individuals with genetically confirmed ACHM with follow-up ranging from about 6 months to 10 years were imaged using either Bioptigen or Cirrus OCT. Foveal cone structure was evaluated by assessing EZ integrity and ONL thickness. Results A total of 470 OCT images were graded, 243 OD and 227 OS. The baseline distribution of EZ grades was highly symmetrical between eyes (P = 0.99) and there was no significant interocular difference in baseline ONL thickness (P = 0.12). The EZ grade remained unchanged over the follow-up period for 60 of 63 individuals. Foveal ONL thickness showed a clinically significant change in only 1 of the 61 individuals analyzed, although detailed adaptive optics imaging revealed no changes in cone density in this individual. Conclusions ACHM appears to be a generally stable condition, at least over the follow-up period assessed here. As cones are the cellular targets for emerging gene therapies, stable EZ and ONL thickness demonstrate therapeutic potential for ACHM, although other aspects of the visual system need to be considered when determining the best timing for therapeutic intervention.
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Affiliation(s)
- Garrett Grissim
- School of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Ashleigh Walesa
- Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Hannah M. Follett
- Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Brian P. Higgins
- Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Kaitlin Goetschel
- Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Heather Heitkotter
- Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Joseph Carroll
- Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Petersen-Jones SM, Komáromy AM. Canine and Feline Models of Inherited Retinal Diseases. Cold Spring Harb Perspect Med 2024; 14:a041286. [PMID: 37217283 PMCID: PMC10835616 DOI: 10.1101/cshperspect.a041286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Naturally occurring inherited retinal diseases (IRDs) in cats and dogs provide a rich source of potential models for human IRDs. In many cases, the phenotypes between the species with mutations of the homologous genes are very similar. Both cats and dogs have a high-acuity retinal region, the area centralis, an equivalent to the human macula, with tightly packed photoreceptors and higher cone density. This and the similarity in globe size to that of humans means these large animal models provide information not obtainable from rodent models. The established cat and dog models include those for Leber congenital amaurosis, retinitis pigmentosa (including recessive, dominant, and X-linked forms), achromatopsia, Best disease, congenital stationary night blindness and other synaptic dysfunctions, RDH5-associated retinopathy, and Stargardt disease. Several of these models have proven to be important in the development of translational therapies such as gene-augmentation therapies. Advances have been made in editing the canine genome, which necessitated overcoming challenges presented by the specifics of canine reproduction. Feline genome editing presents fewer challenges. We can anticipate the generation of specific cat and dog IRD models by genome editing in the future.
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Affiliation(s)
- Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA
| | - András M Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA
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Stürmer S, Bolz S, Zrenner E, Ueffing M, Haq W. Sustained Extracellular Electrical Stimulation Modulates the Permeability of Gap Junctions in rd1 Mouse Retina with Photoreceptor Degeneration. Int J Mol Sci 2024; 25:1616. [PMID: 38338908 PMCID: PMC10855676 DOI: 10.3390/ijms25031616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Neurons build vast gap junction-coupled networks (GJ-nets) that are permeable to ions or small molecules, enabling lateral signaling. Herein, we investigate (1) the effect of blinding diseases on GJ-nets in mouse retinas and (2) the impact of electrical stimulation on GJ permeability. GJ permeability was traced in the acute retinal explants of blind retinal degeneration 1 (rd1) mice using the GJ tracer neurobiotin. The tracer was introduced via the edge cut method into the GJ-net, and its spread was visualized in histological preparations (fluorescent tagged) using microscopy. Sustained stimulation was applied to modulate GJ permeability using a single large electrode. Our findings are: (1) The blind rd1 retinas displayed extensive intercellular coupling via open GJs. Three GJ-nets were identified: horizontal, amacrine, and ganglion cell networks. (2) Sustained stimulation significantly diminished the tracer spread through the GJs in all the cell layers, as occurs with pharmaceutical inhibition with carbenoxolone. We concluded that the GJ-nets of rd1 retinas remain coupled and functional after blinding disease and that their permeability is regulatable by sustained stimulation. These findings are essential for understanding molecular signaling in diseases over coupled networks and therapeutic approaches using electrical implants, such as eliciting visual sensations or suppressing cortical seizures.
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Affiliation(s)
| | | | | | | | - Wadood Haq
- Institute for Ophthalmic Research, University of Tuebingen, 72076 Tuebingen, Germany
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Yang Z, Yan L, Zhang W, Qi J, An W, Yao K. Dyschromatopsia: a comprehensive analysis of mechanisms and cutting-edge treatments for color vision deficiency. Front Neurosci 2024; 18:1265630. [PMID: 38298913 PMCID: PMC10828017 DOI: 10.3389/fnins.2024.1265630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024] Open
Abstract
Color blindness is a retinal disease that mainly manifests as a color vision disorder, characterized by achromatopsia, red-green color blindness, and blue-yellow color blindness. With the development of technology and progress in theory, extensive research has been conducted on the genetic basis of color blindness, and various approaches have been explored for its treatment. This article aims to provide a comprehensive review of recent advances in understanding the pathological mechanism, clinical symptoms, and treatment options for color blindness. Additionally, we discuss the various treatment approaches that have been developed to address color blindness, including gene therapy, pharmacological interventions, and visual aids. Furthermore, we highlight the promising results from clinical trials of these treatments, as well as the ongoing challenges that must be addressed to achieve effective and long-lasting therapeutic outcomes. Overall, this review provides valuable insights into the current state of research on color blindness, with the intention of informing further investigation and development of effective treatments for this disease.
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Affiliation(s)
- Zihao Yang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenliang Zhang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Jia Qi
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenjing An
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
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Britten-Jones AC, Thai L, Flanagan JPM, Bedggood PA, Edwards TL, Metha AB, Ayton LN. Adaptive optics imaging in inherited retinal diseases: A scoping review of the clinical literature. Surv Ophthalmol 2024; 69:51-66. [PMID: 37778667 DOI: 10.1016/j.survophthal.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Adaptive optics (AO) imaging enables direct, objective assessments of retinal cells. Applications of AO show great promise in advancing our understanding of the etiology of inherited retinal disease (IRDs) and discovering new imaging biomarkers. This scoping review systematically identifies and summarizes clinical studies evaluating AO imaging in IRDs. Ovid MEDLINE and EMBASE were searched on February 6, 2023. Studies describing AO imaging in monogenic IRDs were included. Study screening and data extraction were performed by 2 reviewers independently. This review presents (1) a broad overview of the dominant areas of research; (2) a summary of IRD characteristics revealed by AO imaging; and (3) a discussion of methodological considerations relating to AO imaging in IRDs. From 140 studies with AO outcomes, including 2 following subretinal gene therapy treatments, 75% included fewer than 10 participants with AO imaging data. Of 100 studies that included participants' genetic diagnoses, the most common IRD genes with AO outcomes are CNGA3, CNGB3, CHM, USH2A, and ABCA4. Confocal reflectance AO scanning laser ophthalmoscopy was the most reported imaging modality, followed by flood-illuminated AO and split-detector AO. The most common outcome was cone density, reported quantitatively in 56% of studies. Future research areas include guidelines to reduce variability in the reporting of AO methodology and a focus on functional AO techniques to guide the development of therapeutic interventions.
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Affiliation(s)
- Alexis Ceecee Britten-Jones
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia.
| | - Lawrence Thai
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Jeremy P M Flanagan
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Phillip A Bedggood
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Thomas L Edwards
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Andrew B Metha
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
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7
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Solaki M, Wissinger B, Kohl S, Reuter P. Functional evaluation allows ACMG/AMP-based re-classification of CNGA3 variants associated with achromatopsia. Genet Med 2023; 25:100979. [PMID: 37689994 DOI: 10.1016/j.gim.2023.100979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023] Open
Abstract
PURPOSE CNGA3 encoding the main subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors is one of the major disease-associated genes for achromatopsia. Most CNGA3 variants are missense variants with the majority being functionally uncharacterized and therefore hampering genetic diagnosis. In light of potential gene therapy, objective variant pathogenicity assessment is essential. METHODS We established a medium-throughput aequorin-based luminescence bioassay allowing mutant CNGA3 channel function assessment via quantification of CNGA3 channel-mediated calcium influx in a cell culture system, thereby enabling American College of Medical Genetics and Genomics/Association for Molecular Pathology-based variant re-classification. RESULTS We provide functional read-out obtained for 150 yet uncharacterized CNGA3 missense substitutions of which 55 were previously categorized as variants of uncertain significance (VUS) identifying 25 as functionally normal and 125 as functionally abnormal. These data enabled the American College of Medical Genetics and Genomics/ Association for Molecular Pathology-based variant re-classification of 52/55 VUS as either benign, likely benign, or likely pathogenic reaching a VUS re-classification rate of 94.5%. CONCLUSION Our aequorin-based bioassay allows functionally ensured clinical variant interpretation for 150 CNGA3 missense variants enabling and supporting VUS re-classification and assuring molecular diagnosis to patients affected by CNGA3-associated achromatopsia, hereby identifying patients eligible for future gene therapy trials on this disease.
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Affiliation(s)
- Maria Solaki
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
| | - Peggy Reuter
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
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Eshel YM, Abaev O, Yahalom C. Achromatopsia: Long term visual performance and clinical characteristics. Eur J Ophthalmol 2023:11206721231212768. [PMID: 37920903 DOI: 10.1177/11206721231212768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
BACKGROUND Achromatopsia is an autosomal recessive cone dysfunction syndrome, characterized by absence of color discrimination, low visual acuity, photophobia, and nystagmus. Achromatopsia constitutes a common cause of visual impairment in children, with a prevalence of 1:30,000 worldwide. OBJECTIVE To characterize the clinical characteristics of achromatopsia, the main genes causing the disease in our population and the clinical course of the disease, with an emphasis on visual function stability with increasing age. METHODS Retrospective study based on medical charts of patients with achromatopsia. Patients were divided into two groups according to their age at last follow-up: older and younger than 10 years. A subset of patients with long term follow-up were analyzed separately, with patients being described in both age groups. RESULTS Seventy-six patients were included in the study. The mean age was 14.28 years. Variants in the CNGA3 gene were the most common (73.6%). Clinical characteristics included photophobia (96.2%), nystagmus (93.6%), hypermetropia (72.3%) and strabismus (51.1%). In the large cohort there was no correlation of age with visual acuity (p = 0.129). In the separate subset cohort with long follow-up there was a relative improvement in visual acuity with age (p < 0.001). CONCLUSIONS CNGA3 is the main gene associated with achromatopsia in our population (around ∼ 73%), which is in contrast to the distribution worldwide (∼ 25%). Most achromats suffer from photophobia and nystagmus, and the main refractive error is hypermetropia. Achromatopsia's natural course seems to be stationary, and there may even be a slight improvement in visual acuity with time.
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Affiliation(s)
| | - Ora Abaev
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Claudia Yahalom
- Faculty of Medicine,Hebrew University of Jerusalem, Israel
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
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9
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Danish E, Alhashem A, Aljehani R, Aljawi A, Aldarwish MM, Al Mutairi F, Alfadhel M, Alrifai MT, Alobaisi S. Phenotype and genotype of 15 Saudi patients with achromatopsia: A case series. Saudi J Ophthalmol 2023; 37:301-306. [PMID: 38155673 PMCID: PMC10752271 DOI: 10.4103/sjopt.sjopt_108_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/23/2023] [Accepted: 07/27/2023] [Indexed: 12/30/2023] Open
Abstract
PURPOSE Achromatopsia is a rare stationary retinal disorder that primarily affects the cone photoreceptors. Individuals with achromatopsia present with photophobia, nystagmus, reduced visual acuity (VA), and color blindness. Multiple genes responsible for achromatopsia have been identified (e.g. cyclic nucleotide-gated channel subunit alpha 3 [CNGA3] and activating transcription factor 6). Studies have assessed the role of gene therapy in achromatopsia. Therefore, for treatment and prevention, the identification of phenotypes and genotypes is crucial. Here, we described the clinical manifestations and genetic mutations associated with achromatopsia in patients from Saudi Arabia. METHODS This case series study included 15 patients with clinical presentations, suggestive of achromatopsia, who underwent ophthalmological and systemic evaluations. Patients with typical achromatopsia phenotype underwent genetic evaluation using whole-exome testing. RESULTS All patients had nystagmus (n = 15) and 93.3% had photophobia (n = 14). In addition, all patients (n = 15) had poor VA. Hyperopia with astigmatism was observed in 93.3% (n = 14) and complete color blindness in 93.3% of the patients (n = 14). In the context of family history, both parents of all patients (n = 15) were genetic carriers, with a high consanguinity rate (82%, n = 9 families). Electroretinography showed cone dysfunction with normal rods in 66.7% (n = 10) and both cone-rod dysfunction in 33.3% (n = 5) patients. Regarding the genotypic features, 93% of patients had variants in CNGA3 (n = 14) categorized as pathogenic Class 1 (86.7%, n = 13). Further, 66.7% (n = 10) of patients also harbored the c.661C>T DNA variant. Further, the patients were homozygous for these mutations. Three other variants were also identified: c.1768G>A (13.3%, n = 2), c.830G>A (6.6%, n = 1), and c. 822G >T (6.6%, n = 1). CONCLUSION Consanguinity and belonging to the same tribe are major risk factors for disease inheritance. The most common genotype was CNGA3 with the c.661C>T DNA variant. We recommend raising awareness among families and providing genetic counseling for this highly debilitating disease.
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Affiliation(s)
- Enam Danish
- Department of Ophthalmology, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Amal Alhashem
- Department of Pediatric, Division of Genetic and Metabolic Medicine, Prince Sultan Medical Military City, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Reham Aljehani
- Department of Ophthalmology, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Anan Aljawi
- Department of Ophthalmology, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Manar M. Aldarwish
- Department of Genetics and Precision Medicine, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Fuad Al Mutairi
- Department of Genetics and Precision Medicine, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Centre, Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Department of Genetics and Precision Medicine, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- Department of Medical Genomics Research, King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Muhammad T. Alrifai
- King Abdullah International Medical Research Centre, Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- Pediatric Ophthalmology Division, Department of Pediatric Surgery, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Saif Alobaisi
- Pediatric Ophthalmology Division, Department of Pediatric Surgery, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
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10
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Kugler SA, Valmaggia C, Sturm V, Schorderet DF, Todorova MG. Analysis of Suspected Achromatopsia by Multimodal Diagnostic Testing. Klin Monbl Augenheilkd 2023; 240:1158-1173. [PMID: 37714190 DOI: 10.1055/a-2176-4233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
BACKGROUND Achromatopsia (ACHM) as a hereditary cone disease might manifest in a stationary and progressive manner. The proper clinical and genetic diagnosis may allow an individual prognosis, accurate genetic counselling, and the optimal choice of low vision aids. The primary aim of the study was to determine the spectrum of clinical and genetic diagnostics required to characterize the ACHM. METHODS A retrospective analysis was performed in 8 patients from non-related families (5 ♀,3 ♂); age at diagnosis: 3 - 56 y, mean 18.13 (SD ± 18.22). Clinical phenotyping, supported by colour vision test, fundus photography-, autofluorescence- (FAF), infra-red- (IR), OCT imaging and electroretinography provided information on the current status and the course of the disease over the years. In addition, genetic examinations were performed with ACHM relevant testing (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H and the transcription factor ATF6). RESULTS All patients suffered photophobia and reduced visual acuity (mean: 0.16 [SD ± 0.08]). Nystagmus was identified in 7 from 8 subjects and in one patient a head-turn right helped to reduce the nystagmus amplitude. Colour vision testing confirmed complete achromatopsia in 7 out of 8 patients. Electrophysiology found severely reduced photopic- but also scotopic responses. Thinning and interruption of the inner segment ellipsoid (ISe) line within the macula but also FAF- and IR abnormalities in the fovea and/or parafovea were characteristic in all ACHM patients. Identification of pathogenic mutations in 7 patients helped to confirm the diagnosis of ACHM (3 adults, 4 children; 3 ♀ and 4 ♂). Achromatopsia was linked to CNGA3 (2 ♀, 1 ♂) and CNGB3 variants (2 ♀, 3 ♂). The youngest patient (♀, 10 y) had 3 different CNGB3 variants on different alleles. In a patient (♂, 29 y) carrying 2 pathogenic digenic-triallelic CNGA3- and CNGB3-mutations, a severe progression of ISe discontinuity to coloboma-like macular atrophy was observed during the 12-year follow-up. The oldest female (67 y) showed a compound homozygous CNGA3- and heterozygous CNGB3-, as well as a heterozygous GUCY2D variants. The destruction of her ISe line was significantly enlarged and represented a progressive cone-rod phenotype in comparison to other ACHM patients. In a patient (♂, 45 y) carrying a pathogenic CNGB3 and USH2 mutation, a severe macular oedema and a rod-cone phenotype was observed. In addition, two variants in C2ORF71 considered as VOS were found. One patient showed the rare ATF6 mutation, where a severe coloboma-like macular atrophy was observed on the left eye as early as at the age of three years. CONCLUSION Combining multimodal ophthalmological diagnostics and molecular genetics when evaluating patients with ACHM helps in characterizing the disease and associated modifiers, and is therefore strongly recommended for such patients.
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Affiliation(s)
- Sylvia A Kugler
- Department of Ophthalmology, Cantonal Hospital St. Gallen, Switzerland
| | - Christophe Valmaggia
- Department of Ophthalmology, Cantonal Hospital St. Gallen, Switzerland
- Department of Ophthalmology, University of Zürich, Switzerland
| | - Veit Sturm
- Department of Ophthalmology, University of Zürich, Switzerland
- Ophthalmology, Eye Center Rosengarten, Arbon, Switzerland
| | - Daniel F Schorderet
- Faculty of Biology and Medicine, University of Lausanne and Faculty of Life Sciences, École polytechnique fédérale de Lausanne, Switzerland
| | - Margarita G Todorova
- Department of Ophthalmology, Cantonal Hospital St. Gallen, Switzerland
- Department of Ophthalmology, University of Zürich, Switzerland
- Department of Ophthalmology, University Hospital Basel, Switzerland
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11
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Käsmann-Kellner B, Hoffmann MB. [Achromatopsia : Clinical aspects, diagnostics, genes, brain and quality of life]. DIE OPHTHALMOLOGIE 2023; 120:975-986. [PMID: 37638972 DOI: 10.1007/s00347-023-01904-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/14/2023] [Indexed: 08/29/2023]
Abstract
Achromatopsia or rod monochromatism is a congenital autosomal recessive retinal dystrophy which leads to dysfunctional cones, with decreased visual acuity, extremely limited color vision, nystagmus and photophobia. Due to the initially normally appearing ocular morphology, the diagnosis is often delayed. With imaging procedures, e.g., fluorescence-autofluorescence (FAF) and optical coherence tomography (OCT), different morphological forms of achromatopsia can be discriminated that do not seem to have a differential effect on visual function. Crucial is the provision of specific edge filters. Mutations in six genes are known to cause achromatopsia. For the two most frequent genes, CNGA3 and CNGB3, gene addition therapies are currently being tested. Such future approaches should be applied before the manifestation of sensory-related amblyopia in the visual cortex. Accordingly, state of the art management of achromatopsia should provide a diagnosis in early childhood including genotyping.
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Affiliation(s)
- Barbara Käsmann-Kellner
- Klinik für Augenheilkunde, Sektion KiOLoN: Kinderophthalmologie, Orthoptik, Low Vision und Neuroophthalmologie, Universitätsklinikum des Saarlandes UKS, Kirrbergerstr. 100, 66421, Homburg/Saar, Deutschland.
| | - Michael B Hoffmann
- Universitäts-Augenklinik Magdeburg, Magdeburg, Deutschland
- Center for Behavioral Brain Sciences, Magdeburg, Deutschland
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Friebe A, Kraehling JR, Russwurm M, Sandner P, Schmidtko A. The 10th International Conference on cGMP 2022: recent trends in cGMP research and development-meeting report. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:1669-1686. [PMID: 37079081 PMCID: PMC10338386 DOI: 10.1007/s00210-023-02484-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/31/2023] [Indexed: 04/21/2023]
Abstract
Increasing cGMP is a unique therapeutic principle, and drugs inhibiting cGMP-degrading enzymes or stimulating cGMP production are approved for the treatment of various diseases such as erectile dysfunction, coronary artery disease, pulmonary hypertension, chronic heart failure, irritable bowel syndrome, or achondroplasia. In addition, cGMP-increasing therapies are preclinically profiled or in clinical development for quite a broad set of additional indications, e.g., neurodegenerative diseases or different forms of dementias, bone formation disorders, underlining the pivotal role of cGMP signaling pathways. The fundamental understanding of the signaling mediated by nitric oxide-sensitive (soluble) guanylyl cyclase and membrane-associated receptor (particulate) guanylyl cyclase at the molecular and cellular levels, as well as in vivo, especially in disease models, is a key prerequisite to fully exploit treatment opportunities and potential risks that could be associated with an excessive increase in cGMP. Furthermore, human genetic data and the clinical effects of cGMP-increasing drugs allow back-translation into basic research to further learn about signaling and treatment opportunities. The biannual international cGMP conference, launched nearly 20 years ago, brings all these aspects together as an established and important forum for all topics from basic science to clinical research and pivotal clinical trials. This review summarizes the contributions to the "10th cGMP Conference on cGMP Generators, Effectors and Therapeutic Implications," which was held in Augsburg in 2022 but will also provide an overview of recent key achievements and activities in the field of cGMP research.
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Affiliation(s)
- Andreas Friebe
- Institute of Physiology, University of Würzburg, Röntgenring 9, D-97070 Würzburg, Germany
| | - Jan R. Kraehling
- Pharmaceuticals, Research and Early Development, Pharma Research Center, Bayer AG, Aprather Weg 18a, D-42096 Wuppertal, Germany
| | - Michael Russwurm
- Institute of Pharmacology, Ruhr-University Bochum, Universitätsstr. 150, D-44801 Bochum, Germany
| | - Peter Sandner
- Pharmaceuticals, Research and Early Development, Pharma Research Center, Bayer AG, Aprather Weg 18a, D-42096 Wuppertal, Germany
- Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Achim Schmidtko
- Institute of Pharmacology and Clinical Pharmacy, Goethe University, Max-Von-Laue-Str. 9, D-60438 Frankfurt Am Main, Germany
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Priglinger CS, Gerhardt MJ, Rudolph G, Priglinger SG, Michalakis S. [Gene therapy in ophthalmology]. DIE OPHTHALMOLOGIE 2023; 120:867-882. [PMID: 37418021 DOI: 10.1007/s00347-023-01883-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/25/2023] [Indexed: 07/08/2023]
Abstract
In 2017 the gene therapy medication voretigene neparvovec-rzyl was approved by the U.S. Food and Drug Administration (FDA) for retinal gene therapy of hereditary retinal dystrophies caused by mutations in the RPE65 gene. Voretigene neparvovec-rzyl is a gene augmentation therapy using an adeno-associated virus-based vector to express a healthy copy of the human RPE65 gene in the patient's retinal pigment epithelial (RPE) cells. The success of gene augmentation therapy in RPE65-linked retinal dystrophy encouraged research activities on the concept of gene supplementation to be extended to nongenetic diseases, such as age-related macular degeneration; however, it also showed that the principle of success cannot be easily extended to other retinal dystrophies. This review article presents the most commonly used principles and technologies of gene therapy and provides an overview of the current challenges and limitations. Furthermore, practice-relevant aspects of the indications and the treatment procedure are discussed. Particular attention is paid to the consideration of disease stages, especially with respect to patient's expectations and the evaluation of treatment success.
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Affiliation(s)
- Claudia S Priglinger
- Augenklinik, Ludwig-Maximilians-Universität München, Mathildenstr. 8, 80336, München, Deutschland.
| | - Maximilian J Gerhardt
- Augenklinik, Ludwig-Maximilians-Universität München, Mathildenstr. 8, 80336, München, Deutschland
| | - Günther Rudolph
- Augenklinik, Ludwig-Maximilians-Universität München, Mathildenstr. 8, 80336, München, Deutschland
| | - Siegfried G Priglinger
- Augenklinik, Ludwig-Maximilians-Universität München, Mathildenstr. 8, 80336, München, Deutschland
| | - Stylianos Michalakis
- Augenklinik, Ludwig-Maximilians-Universität München, Mathildenstr. 8, 80336, München, Deutschland
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Chan C, Seitz B, Käsmann-Kellner B. Morphological and Functional Aspects and Quality of Life in Patients with Achromatopsia. J Pers Med 2023; 13:1106. [PMID: 37511719 PMCID: PMC10381746 DOI: 10.3390/jpm13071106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/02/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
(1) Background: Achromatopsia is a rare disease of which the natural course and impact on life are still unknown to this date. We aimed to assess the morphological, functional characteristics, and quality of life in a large sample size of patients with achromatopsia. (2) A total of 94 achromats were included in this retrospective cohort study. Sixty-four were patients of the Department of Ophthalmology, Saarland University Medical Centre in Homburg/Saar, Germany, between 2008 and 2021. Thirty further participants with achromatopsia from the national support group were included using an online questionnaire, which is available under 'Supplementary data'. Statistical analysis was performed using SPSS Version 25; (3) The 94 patients (37 males (39.4%) and 57 females (60.6%)) showed a mean age of 24.23 ± 18.53 years. Visual acuity was stable (SD ± 0.22 logMAR at 1.0 logMAR) over a time of observation from 2008 to 2021. Edge filter glasses were the most used optical aids, while enlarged reading glasses were the most used low vision aids. (4) Conclusions: Our findings give an insight into describing the natural process and the quality of life of achromatopsia. The results demonstrate that achromatopsia is a predominantly stationary disease. The individual prescription of edge filters and low-vision aids is essential following a personalised fitting.
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Affiliation(s)
- Caroline Chan
- Department of Ophthalmology, University of Saarland Medical Center in Homburg/Saar, 66421 Homburg/Saar, Germany
| | - Berthold Seitz
- Department of Ophthalmology, University of Saarland Medical Center in Homburg/Saar, 66421 Homburg/Saar, Germany
| | - Barbara Käsmann-Kellner
- Department of Ophthalmology, University of Saarland Medical Center in Homburg/Saar, 66421 Homburg/Saar, Germany
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Amaral RAS, Motta FL, Zin OA, da Palma MM, Rodrigues GD, Sallum JMF. Molecular and Clinical Characterization of CNGA3 and CNGB3 Genes in Brazilian Patients Affected with Achromatopsia. Genes (Basel) 2023; 14:1296. [PMID: 37372476 DOI: 10.3390/genes14061296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 06/29/2023] Open
Abstract
Achromatopsia (ACHM) is a congenital cone photoreceptor disorder characterized by reduced visual acuity, nystagmus, photophobia, and very poor or absent color vision. Pathogenic variants in six genes encoding proteins composing the cone phototransduction cascade (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2) and of the unfolded protein response (ATF6) have been related to ACHM cases, while CNGA3 and CNGB3 alone are responsible for most cases. Herein, we provide a clinical and molecular overview of 42 Brazilian patients from 38 families affected with ACHM related to biallelic pathogenic variants in the CNGA3 and CNGB3 genes. Patients' genotype and phenotype were retrospectively evaluated. The majority of CNGA3 variants were missense, and the most prevalent CNGB3 variant was c.1148delC (p.Thr383Ilefs*13), resulting in a frameshift and premature stop codon, which is compatible with previous publications in the literature. A novel variant c.1893T>A (p.Tyr631*) in the CNGB3 gene is reported for the first time in this study. A great variability in morphologic findings was observed in our patients, although no consistent correlation with age and disease stage in OCT foveal morphology was found. The better understanding of the genetic variants landscape in the Brazilian population will help in the diagnosis of this disease.
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Affiliation(s)
- Rebeca A S Amaral
- Department of Ophthamology, Federal University of São Paulo (UNIFESP), São Paulo 04023-062, Brazil
- Instituto de Genética Ocular, São Paulo 04552-050, Brazil
| | | | - Olivia A Zin
- Department of Ophthamology, Federal University of São Paulo (UNIFESP), São Paulo 04023-062, Brazil
- Instituto Brasileiro de Oftalmologia (IBOL), Rio de Janeiro 22250-040, Brazil
| | - Mariana M da Palma
- Department of Ophthamology, Federal University of São Paulo (UNIFESP), São Paulo 04023-062, Brazil
- Instituto de Genética Ocular, São Paulo 04552-050, Brazil
- Department of Surgery & Hospital Clinic of Barcelona, School of Medicine, Universitat de Barcelona, 08007 Barcelona, Spain
| | - Gabriela D Rodrigues
- Department of Ophthamology, Federal University of São Paulo (UNIFESP), São Paulo 04023-062, Brazil
| | - Juliana M F Sallum
- Department of Ophthamology, Federal University of São Paulo (UNIFESP), São Paulo 04023-062, Brazil
- Instituto de Genética Ocular, São Paulo 04552-050, Brazil
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Choi YJ, Joo K, Lim HT, Kim SS, Han J, Woo SJ. Clinical and Genetic Features of Korean Patients with Achromatopsia. Genes (Basel) 2023; 14:519. [PMID: 36833446 PMCID: PMC9957537 DOI: 10.3390/genes14020519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/14/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
This multicenter study aimed to characterize Korean patients with achromatopsia. The patients' genotypes and phenotypes were retrospectively evaluated. Twenty-one patients (with a mean age at the baseline of 10.9 years) were enrolled and followed up for a mean of 7.3 years. A targeted gene panel or exome sequencing was performed. The pathogenic variants of the four genes and their frequencies were identified. CNGA3 and PDE6C were equally the most prevalent genes: CNGA3 (N = 8, 38.1%), PDE6C (N = 8, 38.1%), CNGB3 (N = 3, 14.3%), and GNAT2 (N = 2, 9.5%). The degree of functional and structural defects varied among the patients. The patients' age exhibited no significant correlation with structural defects. During the follow-up, the visual acuity and retinal thickness did not change significantly. In CNGA3-achromatopsia patients, a proportion of patients with a normal foveal ellipsoid zone on the OCT was significantly higher than that of patients with other causative genes (62.5% vs. 16.7%; p = 0.023). In PDE6C-achromatopsia patients, the same proportion was significantly lower than that of patients with other causative genes (0% vs. 58.3%; p = 0.003). Korean patients with achromatopsia showed similar clinical features but a higher prevalence of PDE6C variants than those of other ethnic groups. The retinal phenotypes of the PDE6C variants were more likely to be worse than those of other genes.
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Affiliation(s)
- Yong Je Choi
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Hyun Taek Lim
- Department of Ophthalmology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, Republic of Korea
- Orthopia Eye Clinic, Seoul 06162, Republic of Korea
| | - Sung Soo Kim
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Republic of Korea
| | - Se Joon Woo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
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Siles L, Gaudó P, Pomares E. High-Efficiency CRISPR/Cas9-Mediated Correction of a Homozygous Mutation in Achromatopsia-Patient-Derived iPSCs. Int J Mol Sci 2023; 24:ijms24043655. [PMID: 36835061 PMCID: PMC9964936 DOI: 10.3390/ijms24043655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/03/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023] Open
Abstract
Achromatopsia is an autosomal recessive disorder, in which cone photoreceptors undergo progressive degeneration, causing color blindness and poor visual acuity, among other significant eye affectations. It belongs to a group of inherited retinal dystrophies that currently have no treatment. Although functional improvements have been reported in several ongoing gene therapy studies, more efforts and research should be carried out to enhance their clinical application. In recent years, genome editing has arisen as one of the most promising tools for personalized medicine. In this study, we aimed to correct a homozygous PDE6C pathogenic variant in hiPSCs derived from a patient affected by achromatopsia through CRISPR/Cas9 and TALENs technologies. Here, we demonstrate high efficiency in gene editing by CRISPR/Cas9 but not with TALENs approximation. Despite a few of the edited clones displaying heterozygous on-target defects, the proportion of corrected clones with a potentially restored wild-type PDE6C protein was more than half of the total clones analyzed. In addition, none of them presented off-target aberrations. These results significantly contribute to advances in single-nucleotide gene editing and the development of future strategies for the treatment of achromatopsia.
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Affiliation(s)
- Laura Siles
- Fundació de Recerca de l’Institut de Microcirurgia Ocular, 08035 Barcelona, Spain
- Departament de Genètica, IMO Grupo Miranza, 08035 Barcelona, Spain
| | - Paula Gaudó
- Fundació de Recerca de l’Institut de Microcirurgia Ocular, 08035 Barcelona, Spain
- Departament de Genètica, IMO Grupo Miranza, 08035 Barcelona, Spain
| | - Esther Pomares
- Fundació de Recerca de l’Institut de Microcirurgia Ocular, 08035 Barcelona, Spain
- Departament de Genètica, IMO Grupo Miranza, 08035 Barcelona, Spain
- Correspondence:
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Clinical-genetic findings in a group of subjects with macular dystrophies due to mutations in rare inherited retinopathy genes. Graefes Arch Clin Exp Ophthalmol 2023; 261:353-365. [PMID: 35947183 DOI: 10.1007/s00417-022-05786-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 07/03/2022] [Accepted: 07/22/2022] [Indexed: 01/25/2023] Open
Abstract
PURPOSE To describe the results of clinical and molecular analyses in a group of patients suffering from inherited macular dystrophies, in which next-generation sequencing (NGS) efficiently detected rare causative mutations. METHODS A total of eight unrelated Mexican subjects with a clinical and multimodal imaging diagnosis of macular dystrophy were included. Visual assessment methods included best corrected visual acuity, color fundus photography, Goldmann visual field tests, kinetic perimetry, dark/light adapted chromatic perimetry, full-field electroretinography, autofluorescence imaging, and spectral domain-optical coherence tomography imaging. Genetic screening was performed by means of whole exome sequencing with subsequent Sanger sequencing validation of causal variants. RESULTS All patients exhibited a predominantly macular or cone-dominant disease. Patients' ages ranged from 12 to 60 years. Three cases had mutations in genes associated with autosomal dominant inheritance (UNC119 and PRPH2) while the remaining five cases had mutations in genes associated with autosomal recessive inheritance (CNGA3, POC1B, BEST1, CYP2U1, and PROM1). Of the total of 11 different pathogenic alleles identified, three were previously unreported disease-causing variants. CONCLUSIONS Macular dystrophies can be caused by defects in genes that are not routinely analyzed or not included in NGS gene panels. In this group of patients, whole exome sequencing efficiently detected rare genetic causes of hereditary maculopathies, and our findings contribute to expanding the current knowledge of the clinical and mutational spectrum associated with these disorders.
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Biology, Pathobiology and Gene Therapy of CNG Channel-Related Retinopathies. Biomedicines 2023; 11:biomedicines11020269. [PMID: 36830806 PMCID: PMC9953513 DOI: 10.3390/biomedicines11020269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
The visual process begins with the absorption of photons by photopigments of cone and rod photoreceptors in the retina. In this process, the signal is first amplified by a cyclic guanosine monophosphate (cGMP)-based signaling cascade and then converted into an electrical signal by cyclic nucleotide-gated (CNG) channels. CNG channels are purely ligand-gated channels whose activity can be controlled by cGMP, which induces a depolarizing Na+/Ca2+ current upon binding to the channel. Structurally, CNG channels belong to the superfamily of pore-loop cation channels and share structural similarities with hyperpolarization-activated cyclic nucleotide (HCN) and voltage-gated potassium (KCN) channels. Cone and rod photoreceptors express distinct CNG channels encoded by homologous genes. Mutations in the genes encoding the rod CNG channel (CNGA1 and CNGB1) result in retinitis-pigmentosa-type blindness. Mutations in the genes encoding the cone CNG channel (CNGA3 and CNGB3) lead to achromatopsia. Here, we review the molecular properties of CNG channels and describe their physiological and pathophysiological roles in the retina. Moreover, we summarize recent activities in the field of gene therapy aimed at developing the first gene therapies for CNG channelopathies.
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Jung R, Kempf M, Pohl L, Kortüm F, Reith M, Kelbsch C, Kohl S, Wilhelm H, Wilhelm B, Stingl K, Stingl K. Frequency-dependent retinal responsiveness to sinusoidal electrical stimulation in achromatopsia. Exp Eye Res 2023; 226:109349. [PMID: 36516904 DOI: 10.1016/j.exer.2022.109349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/15/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
Recently, we proposed a method to assess cell-specific retinal functions based on the frequency-dependent responses to sinusoidal transcorneal electrostimulation. In this study, we evaluated the alterations in responsiveness in achromatopsia patients to explore the frequency-selectivity of photoreceptors. The electrical stimulation was applied to one eye of genetically confirmed achromatopsia patients via corneal electrodes. The stimulus was composed of amplitude-modulated sine waves with variable carrier frequencies (4-30 Hz) and a steady low-frequency envelope. The retinal responsiveness across the spectrum was calculated based on the velocity and the synchronicity of the electrically evoked pupillary oscillations. Achromats displayed a characteristic peak in responsiveness in the 6-10 Hz range. In contrast, stimulus frequencies above 16 Hz elicited only weak pupil responses and weak phosphenes. Compared to the tuning curve of the healthy retina, responses to low-frequency stimulation appear to reflect mainly rod activation while higher frequencies seem to activate cones. The possibility to examine cell-specific retinal functions independently from their responses to light may improve our understanding of the structural changes in the retina induced by gene therapy.
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Affiliation(s)
- Ronja Jung
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany.
| | - Melanie Kempf
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Center for Rare Eye Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Lisa Pohl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Friederike Kortüm
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Milda Reith
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Carina Kelbsch
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Helmut Wilhelm
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Barbara Wilhelm
- Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Katarina Stingl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Center for Rare Eye Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Krunoslav Stingl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Center for Rare Eye Diseases, University of Tuebingen, 72076, Tuebingen, Germany
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A Bioengineered In Vitro Model to Assess AAV-Based Gene Therapies for Cyclic GMP-Related Disorders. Int J Mol Sci 2022; 23:ijms23094538. [PMID: 35562929 PMCID: PMC9101586 DOI: 10.3390/ijms23094538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/13/2022] [Accepted: 04/18/2022] [Indexed: 02/01/2023] Open
Abstract
The emergence of efficient viral vectors derived from adeno-associated viruses (AAV) has led many groups to develop gene therapies for inherited monogenic diseases, such as retinal dystrophies. To evaluate the potency of new gene therapy vectors in a preclinical context, it is common to use animal models, such as gene-deficient or mutant animal models of a given human disease, and then assess vision restoration with functional or behavioral assays. While such animal models are invaluable to the preclinical testing process, they cannot be readily used as batch release tests during manufacturing or to validate biological activity at later stages of development. There is therefore a need for rapid and reliable in vitro models that can determine whether therapeutic vectors have delivered their cargo gene, and more importantly, whether this has resulted in the intended biological activity. Given our previous experience, we chose CNGA3-linked achromatopsia to develop a cell-based system to verify biological activity of AAV vectors designed to deliver a healthy CNGA3 gene copy into human cone photoreceptors. Our system is based on an immortalized cell line with high susceptibility to AAV transduction, i.e., HeLa cells, which we engineered to express a fungal rhodopsin guanylyl cyclase (RhGC) from Blastocladiella emersonii and a sensitive genetically encoded calcium indicator (GECI) under the control of a tetracycline operator. Using this system, we were able to confirm and quantify the function of the ion channel encoded by AAV/CNGA3 and differentiate between AAV vector potencies with a simple fluorometric assay. Finally, we show that this approach can be readily adapted for the assessment of phosphodiesterase function.
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22
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Developing Non-Human Primate Models of Inherited Retinal Diseases. Genes (Basel) 2022; 13:genes13020344. [PMID: 35205388 PMCID: PMC8872446 DOI: 10.3390/genes13020344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 01/31/2022] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Abstract
Inherited retinal diseases (IRDs) represent a genetically and clinically heterogenous group of diseases that can eventually lead to blindness. Advances in sequencing technologies have resulted in better molecular characterization and genotype–phenotype correlation of IRDs. This has fueled research into therapeutic development over the recent years. Animal models are required for pre-clinical efficacy assessment. Non-human primates (NHP) are ideal due to the anatomical and genetic similarities shared with humans. However, developing NHP disease to recapitulate the disease phenotype for specific IRDs may be challenging from both technical and cost perspectives. This review discusses the currently available NHP IRD models and the methods used for development, with a particular focus on gene-editing technologies.
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